1. Field of the Invention
This invention relates to providing a quick setup method for holding via vacuum materials to be machined on CNC routers or similar equipment.
2. Description of the Prior Art
Typically all CNC routers or similar equipment are equipped with a vacuum source. The vacuum generated by this source is the means used to hold a workpiece via different apparatuses during the machining operation.
There are generally two methods of setting up of a router bed so that the bed holds workpieces in the proper position for machining. The oldest and most common is manually. Another more recent method is to use programmable elevated/retracted pods that are vertically positioned via computer commands. The manual method, while less expensive, typically requires a complicated and time-intensive setup procedure over the automated one.
Accordingly, the need remains for an improved manual method for setting up a router bed.
The current invention reduces the time required to position mounting jigs (pucks) that hold a workpiece during machining. The, system taught herein is composed of an airtight sheet of material (phenolic or like products) placed on top of the machining bed of the CNC router. An array of evenly spaced cavities are machined into the surface of this material and a magnetically-based valve constructed according to the present invention is placed into each cavity. Once all the machined cavities are filled with the magnetically based valve, the table surface is airtight so as not to allow any atmosphere to be drawn through the table when the vacuum pump is turned on.
The operating principal behind the valve is based on the natural attraction of magnets to one another. A magnet (xe2x80x9cvalve magnetxe2x80x9d) is placed in the valve on a rubber seat so as to block a port in the bottom of the valve when vacuum is turned on. When an operator wants to have a valve opened he/she places a fixture or xe2x80x9cpuckxe2x80x9d that contains an attracting magnet (xe2x80x9cactivator magnetxe2x80x9d) over the valve body. The valve magnet fit into a cavity in the top of the valve body and the attracting force of the activator magnet pulls the magnet contained in the valve off of the rubber seat. When the valve magnet is pulled from the seat, atmosphere is allowed to flow through the valve body.
Preferably, these fixtures are made with gaskets or O-rings positioned around their parameter. The gaskets create a vacuum barrier when a workpiece is placed onto the fixture. Once the workpiece is placed onto the fixture, it in effect creates a seal that stops the flow of atmosphere through it and thus achieves a vacuum chucking effect that holds the workpiece to the fixture. The force of the vacuum chucking pressure further prevents the workpiece from moving during the machining operation.
Two unique advantages are achieved using this system. First the activator magnet on the base of the material holding fixture (puck) opens the valve when the activator magnet is positioned into the cavity of the magnetically based valve configured according to the present invention. This eliminates the need to pull plugs, drill holes into a fixture board or fit gasketing into grooves machined into the table that act as vacuum dams. The second unique advantage is that the activator magnet also act as position locators. By placing numbers consecutively into the bottom of each cavity the operator can receive a pre-machining set-up sheet that tells the operator which valves to cover with the pucks. This eliminates the need to reference the fixture or the workpiece from a known position.
In short, the valves of the present invention create an airtight vacuum bed except in those locations in which pucks having activator magnet are received. This results in the activator magnet attracting the valve magnet, and pulling it from the seat to allow atmosphere to flow through the valve body. Fixturing is used to hold the workpiece above the base level of the table and thereby preventing routing tools from easily passing through the workpiece and impacting upon the surface of the table. By allowing vacuum to pass through the puck fixtures, a seal is formed where the workpiece is placed onto the fixtures and the workpiece is held securely in one position during the machining operation. It should also be understood that when the activator magnet is removed from a valve cavity, the magnet in the valve falls over the vacuum port in the bottom of the valve and thereby blocking atmosphere from passing through the valve.
Besides part holding fixtures, there can be a myriad of other fixtures that may contain clamps, rollers, slides, sensors, etc. The one thing any fixture must have in common is that it contain one or more activator magnets.
Finally, the magnetically-based valve can be used in many applications such as Down-draft tables to hold a workpiece still while being hand sanded, or they can be used in a frame clamping table for positioning and holding the pneumatic clamps secure. Characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.